Does Vitamin C Help With Allergies? - A Closer Look

Itchy eyes, stuffy noses, sneezing, ear congestion—they’re all the classic signs of allergic rhinitis, more commonly known as seasonal allergies or hay fever.

Roughly 8% of Americans experience seasonal allergies annually, and although they’re much more common in the summer months, some people experience them year-round.

There’s no denying that allergies can be a pain in the butt, and while popping back some allergy medicine may provide temporary relief, there are plenty of natural anti-histamines and even vitamins and minerals that can help reduce symptoms.

If you’re tired of dealing with allergy symptoms, you may want to consider popping back some vitamin C. We’re diving into everything you need to know about allergies and how this powerful immune booster may kick your allergy symptoms to the curb.

What Causes Seasonal Allergies?

If you’re someone who experiences congestion, sneezing, and itchiness seasonally, you’re likely dealing with allergic rhinitis. It can arise from any number of things—seasonal pollens and molds, dust, mites, pet hair, etc.—that cause an IgE-mediated reaction against the inhaled allergens, as well as mucosal inflammation driven by type 2 helper T (Th2) cells ¹.

Allergies affect roughly 10 to 20% of the general population and peak between age 20 and 40, then gradually decline after ¹. And although you may not think allergies cause major issues, they can, in fact, lead to absence or lack of productivity at work and school, and with children can lead to a lack of involvement in outdoor activities. And for people who struggle with asthma, the risk of allergic rhinitis increases.

For most people, allergies kick up in the spring when trees flower and disperse their pollen. During late spring and early summer, grasses and weeds introduce yet another round of allergies, and come late summer, ragweed causes another hit.

But what actually causes seasonal allergies?

Allergic rhinitis was considered to be a localized disorder affecting the nose and nasal passages, but more recent evidence suggests that seasonal allergies may actually affect the entire respiratory tract ².

Because there’s a lot of overlap between the upper and lower respiratory tracts, allergies affecting the upper airways causes a local inflammatory response but also trigger inflammation in the lower airways.

Upon exposure to an allergen, several inflammatory cells are activated and infiltrate the nasal lining, including ²:

• Mast cells
• CD4-positive T cells
• B cells
• Macrophages
• Eosinophils

T-cells, specifically, release cytokines (IL-3, IL-4, IL-5, IL-13) in the nasal passages that promote the production of immunoglobulin E (IgE), which triggers the release of inflammatory mediators like histamine and leukotrienes; these cells are responsible for triggering many of the symptoms of allergies—increased vascular permeability, itchiness, runny nose, mucous secretion, and congestion ³.

Typically, there are two classifications of allergic rhinitis: seasonal (occurs in certain seasons) or perennial (occurs year-round). However, where you live is a significant factor in how often you experience allergies.

Symptoms Of Allergies

Seasonal allergies range dramatically between people and can be very mild or severe, but commonly you’ll see ⁴:

• Sneezing
• Runny nose or stuffy nose
• Clogged sinuses and congestion
• Itchy throat or ears
• Plugged ears
• Postnasal drainage

Some less common symptoms are:

Receive unique insights, advice and exclusive offers.

Email address Subscribe

• Headaches
• Coughing
• Wheezing
• Shortness of breath

Can Vitamin C Help Allergies?

If there is one vitamin that’s a powerhouse for your immune system, you know it’s got to be vitamin C. As a potent antioxidant and natural antihistamine, vitamin C is a great natural option for reducing the symptoms of allergies.

Within the immune system, vitamin C plays a number of key roles ⁵:

• Epithelial barriers: Enhances collagen synthesis, prevents free-radical damage, boosts keratinocyte differentiation and lipid synthesis, reduces wound healing time
• Phagocytes: Acts as an antioxidant, increases motility, enhances phagocytosis and ROS production, supports microbial killing, facilitates apoptosis (programmed cell death)
• B- and T-lymphocytes: Boosts differentiation and proliferation, increases antibody levels
• Inflammatory mediators: Regulates cytokine production, decreases histamine levels

One of the main reasons vitamin C is such a powerful nutrient for allergies is its role as an anti-histamine. Histamine is a powerful immune mediator produced by various immune cells (basophils, eosinophils, mast cells) when an immune response is mounted ⁵. It causes vasodilation and increased capillary permeability, thereby causing the classic symptoms of allergies like runny nose and eyes.

Several animal studies on guinea pigs, a rodent that cannot produce vitamin C (like humans), have shown that vitamin C depletion increases circulating histamine levels, while supplementation to restore levels reduces histamine ^{6, 7}. Higher levels of histamine were found to increase the utilization of vitamin C, suggesting that vitamin C may help to “detoxify” histamine from the body.

But unlike over-the-counter anti-histamines you find at the drugstore, vitamin C doesn’t work to block histamine receptors. Rather, it reduces the amount of histamine your body produces to limit allergy symptoms.

Just 2 grams (2,000 mg) of vitamin C daily can reduce histamine levels by a whopping 38% ^{4, 8, 9}. And if you opt for an IV infusion of vitamin C, it could reduce histamine levels by more than 50% ¹⁰.

That said, vitamin C may not work on all allergies.

It appears most beneficial for upper respiratory symptoms from seasonal or environmental allergies like mold, dust, pollen, or pet dander ^{4, 11, 12}.

With these types of allergies, the histamine reaction occurs primarily in the nose or sinuses, resulting in the trademark symptoms of allergic rhinitis—sneezing, runny nose, congestion, and watery eyes.

How Much Vitamin C?

The recommended dietary intake of vitamin C is relatively low, but most experts suggest consuming well above the RDI if you’re looking to treat allergies—around 2,000 mg ¹².

Because vitamin C is a water-soluble vitamin, it’s not stored in the body, and therefore the risk of toxicity is minimal. That said, water-soluble vitamins also must be replaced daily to prevent deficiency.

Although experts recommend 2,000 mg for allergies, you can also reap the other benefits of vitamin C by ensuring you’re consuming what your body needs through both supplementation and food. That can be done with a vitamin C flush (i.e. testing for bowel tolerance).

Note that it’s best to do this flush on an empty stomach and on a day when you aren’t planning to go out (and have a toilet available).

Here’s how to do it:

1. Dissolve 2,000 mg of vitamin C powder in water
2. Write down how much vitamin C you consume and at what time
3. Every 20 minutes, consume another 2,000 mg (and note it down)
4. Continue consuming 2,000 mg every 20 minutes until you start to experience loose stools

Once you’ve reached loose stools, you’ve hit your intake maximum—you can knock it back 1,000 mg if you’re worried because intake requirements will differ between people, and the time to reach vitamin C saturation will vary. However, most people will reach it in 2 to 3 hours.